Shed no 3 on the design board. This time I'll make it big enough though I have no doubt whatever the size it will get filled up On a 4m x 4m concrete base, either a pent roof, like its siblings or a single slope roof. Timber framework with corrugated iron sheeting to roof and walls. Not a thing of beauty but pragmatism reigns. Previously I used 4 x 2s at 600mm centres with roof truss corresponding to wall verticals. I have been pondering increasing the spacings to cut down on the fabrication but don't know where to start. I know traditional round roof farm barn trusses were set at 5m c/c with 6 x 4 purlins but thats a bit extreme for me. An engineer friend once told me the strongest part of them was the corrugated sheeting. Somewhere in the middle would be nice. All advice and help sought and gratefully received